The invention relates to as electrical resister the value of which is controllable by a magnetic field.
It is known that a bismuth spiral in a magnetic field of .about.10.sup.4 Oersted for example has a resistance increased by approximately 50%. In addition, semiconductors such as InSb which have a high charge carrier mobility exhibit an increase in their resistance in high magnetic fields in excess of the reduction in mobility. The effect of magnetic fields on superconductors is especially great. If the magnetic field reaches a critical value, superconductivity disappears. This effect is utilized in super conducting switches. In general, however, fields of the order of magnitude of kilo-Oersteds are required in order to produce noticeable effects.